Cross-linked graft polyesters and sized textiles

ABSTRACT

A cross linked graft polyester comprising the reaction product of a mixture of a polyunsaturated vinyl monomer with an acidic monovinyl monomer having at least one carboxyl group with an unsaturated polyester.

This is a division, of application Ser. No. 121,762, filed Feb. 15,1980, now U.S. Pat. No. 4,275,176 which is a continuation application ofapplication Ser. No. 937,690, filed Aug. 28, 1978, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to novel polyester compositions, sizingcompositions, and processes for sizing yarn utilizing said compositionsas binders or coatings for fibrous articles such as spun or continuousfilament textile yarn.

2. Description of the Prior Art

Prior to the weaving operation, continuous filament synthetic fiber warpyarn is usually given a twist of about 5 to 15 turns per inch andtreated with a sizing composition which binds the filaments of the yarntogether so as to strengthen the yarn by rendering it more resistant toabrasive forces to which it is exposed during the subsequent weavingoperation. Sizing materials must confer on the yarn resistance toabrasion as well as provide additional properties such as elasticity,flexibility, and low tack. In addition, the size must be easily removedsubsequent to the weaving operation in order to return the yarn to itsunsized state in which dying treatments are often performed.

Textile sizing compositions are commonly applied to textile fibers fromwater dispersions. In U.S. Pat. No. 3,981,836, it is disclosed that asuitable size can be prepared by copolymerizing a styrene-maleicanhydride copolymer in the presence of an unsaturated dicarboxylic acidand a monohydric or polyhydric alcohol. The composition can be convertedto a water-dispersible polymer by neutralizing some of the carboxylgroups of the resulting copolymer with an alkali metal hydroxide orammonium hydroxide.

It is also known from U.S. Pat. No. 4,002,700 to prepare compositionsuseful as adhesives, coatings, printing inks and binders by reacting adibasic acid component containing an α,β-ethylenically unsaturateddibasic acid with a glycol to form an unsaturated polyester which isreacted with a base to neutralize unreacted carboxyl groups and renderthe polyester water soluble. The water-soluble polyester can be curedutilizing a monovinyl compound subsequent to application to a substrate.

SUMMARY OF THE INVENTION

It has now been discovered that a novel unsaturated polyester useful forsizing synthetic textile yarns or blends thereof with natural fibers,particularly yarn containing spun or continuous filament polyester yarn,can be prepared, in one embodiment of the size of the invention, byfirst preparing an unsaturated polyester by reacting at least onepolyhydric alcohol with at least one dicarboxylic acid reactant selectedfrom the group consisting of a dicarboxylic acid, a correspondingdicarboxylic acid anhydride, dicarboxylic acid esters, theircorresponding acyl halides or mixtures thereof. A minor effectiveproportion, generally about one to about ten mole percent, preferablyabout 2 to about 8 mole percent of said dicarboxylic acid reactant,based upon 100 mole total percent, is an α,β-ethylenically unsaturateddicarboxylic acid reactant. This is reacted with 100 moles total percentof a polyhydric alcohol, preferably a diol or mixtures thereof with apolyhydric alcohol having a functionality greater than two. Theunsaturated polyester obtained is thereafter blended with about 20 toabout 200 percent by weight of a monovinyl monomer reactant based uponthe weight of the unsaturated polyester, said monomer comprising atleast one acidic monovinyl monomer containing at least one carboxylgroup.

Alternatively, said polyester can be prepared utilizing as a proportionof said polyhydric alcohol a minor effective amount of anα,β-ethylenically unsaturated polyhydric alcohol or a minor effectiveproportion of both said dicarboxylic acid reactant and said polyhydricalcohol reactant, α,β-ethylenically unsaturated acid and alcoholreactants. General and preferred proportions are the same as thosedisclosed above.

By the incorporation by blending of at least one monovinyl monomercomprising at least one acidic monovinyl monomer having at least onecarboxyl group into the unsaturated polyester, grafting can take placeupon reaction in situ of the unsaturated polyester with said vinylmonomer subsequent to application of the size on the fiber. In thismanner, a grafted polymer chain with free-carboxylic groups is added tothe unsaturated polyester chain backbone. Sufficient free carboxylgroups are thereby provided in the polyester such that uponneutralization or partial neutralization with a base, a water-soluble orwater-dispersible polyester size composition results. This permits thepolyester size composition to be readily removed subsequent to theweaving operation.

The size composition can be applied to glass fibers which aresubsequently utilized as reinforcing fillers in the preparation ofplastic articles especially those prepared from unsaturated polyesters,in order to improve the physical properties of the resulting plasticarticles.

The unsaturated polyester compositions of the invention are usefulgenerally in the preparation of adhesives, binders, coatings andprinting inks.

DETAILED DESCRIPTION OF THE INVENTION

The invention relates to novel graft polyesters and size compositionspreferably for sizing hydrophobic synthetic yarns or blends thereof withnatural yarns, said sizing composition being especially adapted forreaction in situ. The composition is deposited on a yarn or fiberpreferably at a temperature of about ambient temperature up to about150° C. without utilizing volatile solvents. The use of a blend of anunsaturated polyester with at least one monovinyl monomer wherein about30 to about 100 mole percent of said vinyl monomer contains at least onecarboxyl group allows the application of the composition to a substratewithout the use of volatile solvents. Subsequent graft polymerization insitu provides a sized fiber. Because said size composition contains asufficient number of free-carboxyl groups, partial or completeneutralization of the size composition with a base conferswater-dispersibility or water-solubility upon the size and thus allowsthe size to be easily removed from the fiber subsequent to the weavingprocess. Methods of sizing hydrophobic synthetic yarns, sized yarns andprocesses for the preparation of said sizing composition are alsodisclosed.

In accordance with the present invention, graft polyesters are preparedby the in situ graft polymerization of a monovinyl monomer having atleast one carboxyl group with an unsaturated polyester, said graftpolymerization preferably being carried out by exposure to at least oneof radiation or a temperature of about 80° C. to about 200° C. in thepresence of a free-radical generating initiator. The unsaturatedpolyesters which can be employed in the preparation of the sizingcompositions of the invention are those which contain reactiveα,β-ethylenic unsaturation derived from at least one of dicarboxylicacids containing α, β-ethylenic unsaturation and polyhydric alcohols orpolyols containing α,β-ethylenic unsaturation.

The unsaturated polyesters of this invention can be prepared by standardprocedures. Typically, such procedures involve the reaction ofdicarboxylic acids (or diesters, anhydrides, etc., thereof) withpolyhydric alcohols in the presence of an acid catalyst, for instance,antimony trioxide or an organic titanate, such as tetrabutyl titanate,utilizing heat and reduced pressure as desired. Normally, an excess ofthe volatile polyhydric alcohol is supplied and removed by conventionaltechniques in the latter stages of polymerization. To protect thepolyester from oxidation, an antioxidant such as a hindered phenol canbe added to the reaction mixture.

Useful unsaturated dicarboxylic acid reactants which can be employed inthe preparation of the unsaturated polyester include both aromatic andaliphatic acids which are reactive under conditions of free radicalgraft polymerization and generally are α,β-ethylenically unsaturateddicarboxylic acids or their corresponding dicarboxylic anhydrides,esters and acyl halides. These include, for example, maleic acid,fumaric acid, p-carboxycinnamic acid, itaconic acid, etc. Most of theseacids are α,β-dicarboxylic as well as α,β-ethylenically unsaturated.

The α,β-ethylenically unsaturated dicarboxylic acids can be utilized incombination with saturated dicarboxylic acids. Representative saturateddicarboxylic acid reactants include both aromatic and aliphatic acidsincluding cycloaliphatic dicarboxylic acids and corresponding anhydridesor esters, for example, phthalic, terephthalic, isophthalic, oxalic,malonic, succinic, glutaric, 2,2-dimethylglutaric, adipic, pimelic,azelaic, sebacic, 1,3-cyclopentane dicarboxylic, 1,2-cyclohexanedicarboxylic, 1,3-cyclohexane dicarboxylic, 1,4-cyclohexanedicarboxylic, 2,5-norbornane dicarboxylic, 1,4-naphthalic, diphenic,4,4-oxydibenzoic, 4,4'-sulfonyl dibenzoic, diglycolic, thiodipropionic,and 2,5-naphthalene dicarboxylic acids.

Because of their known contribution to film strength in polyesters, thearomatic diacids such as isophthalic acid or terephthalic acid arepreferred saturated aromatic diacids. Suitable mixtures of thesedicarboxylic acids can be utilized to obtain desired modifications ofphysical properties in the polyester size composition of the inventionas is well known by those skilled in the art. The corresponding estersand acyl halides of the above enumerated dicarboxylic acids can also beused in preparing the novel polyester size compositions of theinvention. Examples of representative dicarboxylic acid esters includedimethyl 1,4-cyclohexanedicarboxylate, dimethyl2,6-naphthalenedicarboxylate, dibutyl 4,4'-sulfonyldibenzoate, dimethylisophthalate, dimethyl terephthalate, and diphenyl terephthalate. Acylhalides are characterized by the general formula RCOX, wherein R isaliphatic, aromatic or cycloaliphatic and X is chlorine. Examples ofuseful compounds are: terephthaloyl dichloride, isophthaloyl dichloride,malonyl dichloride, itaconyl dichloride. Copolyesters can be preparedfrom two or more of the above dicarboxylic reactants or derivativesthereof.

The polyhydric alcohols which are useful in the preparation in theunsaturated polyesters of the invention can be diols or mixtures ofdiols with hydroxyl-containing compounds having a functionality greaterthan two but are preferably diols having 2 to 8 carbon atoms forexample, ethylene glycol; propylene glycol; 1,3-propanediol; neopentylglycol; 2,4-dimethyl-2-ethylhexane-1,3-propanediol;2,2-dimethyl-1,3-propanediol; 2-ethyl-2-butyl-1,3-propanediol;2-ethyl-2-isobutyl-1,3-propanediol; 1,3-butanediol; 1,4-butanediol;1,5-pentanediol; 1,6-hexanediol; 2,2,4-trimethyl-1,6-hexanediol;1,2-cyclohexanedimethanol; 1,3-cyclohexanedimethanol; andbis(hydroxyethyl) hydroquinone.

The unsaturation in the unsaturated polyesters of the invention can beobtained using mixtures of α,β-ethylenically unsaturated dicarboxylicacid reactants and polyhydric alcohols or polyols, or solely by theincorporation of an α,β-ethylenic unsaturation-containing dicarboxylicacid, polyhydric alcohol or polyol as a reactant in the preparation ofthe polyester. A minor effective amount of unsaturation-containingreactant is used, generally about 1 to about 10 mole percent, preferablyabout two to about eight mole percent of α,β-ethylenically unsaturatedpolyhydric alcohol or dicarboxylic acid based upon 100 mole percent ofsaid polyhydric alcohol or said acid is utilized in the preparation ofthe unsaturated polyester of the invention. Where blends of unsaturateddicarboxylic acid reactant and unsaturated polyhydric alcohol reactantare used, a minor effective amount of unsaturated alcohol is used,generally about 1 to about 10 mole percent, preferably about one toabout four mole percent of each of said unsaturated alcohol and acid inthe mixture based upon 100 mole percent of each acid and alcoholreactant will be α,β-ethylenically unsaturated acid or alcoholreactants.

The α,β-ethylenic unsaturation-containing polyol which can be utilizedas a portion of the polyhydric alcohol reactant can be prepared by thereaction of any conventional polyol with an organic compound having bothα,β-ethylenic unsaturation and a hydroxyl, carboxyl or epoxy group.Alternatively, the polyols can be prepared by employing as a reactant inthe preparation of the polyol a compound having both α,β-ethylenicunsaturation and a hydroxy, carboxyl or epoxy group.

A representative listing of organic compounds from which compoundsuseful in the preparation of the α,β-ethylenic unsaturation-containingpolyol can be selected by one skilled in the art includeα,β-ethylenically unsaturated polycarboxylic acids and anhydrides suchas maleic acid and anhydride, fumaric acid and anhydride, crotonic acidand anhydride, propenyl succinic anhydride, and halogenated maleic acidsand anhydrides, unsaturated polyhydric alcohols such as2-butene-1,4-diol, glycerol allylether, trimethylolpropane allylether,pentaerythritol allylether, pentaerythritol vinylether, pentaerythritoldiallylether, and 1-butene-3,4-diol, unsaturated epoxides such as1-vinylcyclohexane-3,4-epoxide, butadiene monoxide, vinyl glycidylether(α-vinyloxy-2,3-epoxy propane), glycidyl methacrylate and3-allyloxypropylene oxide (allyl glycidyl-ether). If a polycarboxylicacid or anhydride is employed to incorporate the required unsaturationinto the polyols so as to provide terminal carboxyl groups, it is thennecessary to react the unsaturated polyol with an alkylene oxide,preferably ethylene or propylene oxide, to replace the carboxyl groupswith hydroxyl groups prior to employment in the present invention.

To prepare α,β-ethylenic unsaturation-containing polyols useful in thepresent invention, from about 0.1 mole to about 3.0 moles, preferablyfrom 0.30 mole to 1.5 moles, of said unsaturated organic compound permole of polyol is employed. Polyols containing relatively lowunsaturation can also be prepared by blending a highunsaturation-containing polyol with a polyol which is free ofα,β-ethylenic unsaturation. If a blend of polyols is employed, theamount of unsaturation should fall within the range stated above. Thepreparation of unsaturation-containing polyols employed in the presentinvention follows conventional prior art procedures such as disclosed inU.S. Pat. No. 3,275,606 and U.S. Pat. No. 3,280,077, incorporated hereinby reference. Generally this requires a reaction at a temperaturebetween 0° C. and 150° C. Both acidic catalysts, such as Lewis acidcatalysts and basic catalysts such as alkali metal hydroxides, may beused. In addition, a non-catalyzed reaction may be used employingtemperatures between 50° C. and 200° C. It is, of course, understoodthat the resulting polyols are a cogeneric mixture of polyols and not asingle molecular structure.

Representative saturated polyols which can be employed in thepreparation of the unsaturated polyester reactant components of theunsaturated polyester-vinyl monomer size composition of the inventionand in the preparation of the unsaturation-containing polyols which canbe employed in the present invention are well known in the art. They areoften prepared by the catalytic condensation of an alkylene oxide ormixture of alkylene oxides either simultaneously or sequentially with anorganic compound having at least two active hydrogen atoms such astaught by U.S. Pat. Nos. 1,922,451; 3,190,927 and 3,346,557,incorporated herein by reference.

Representative saturated polyols include polyhydroxyl-containingpolyesters, polyalkylene polyether polyols, polyhydroxy-terminatedpolyurethane polymers, polyhydroxyl-terminated polycaprolactonepolyesters, and alkylene oxide adducts of polyacetals, and aliphaticpolyols. Generally the equivalent weight of the polyols will vary from500 to 20,000, preferably from 1000 to 5000.

Any suitable hydroxyl-containing polyester (polyester polyol) can beused such as are obtained from polycarboxylic acids and polyhydricalcohols. Any suitable polycarboxylic acid can be used such as oxalicacid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelicacid, suberic acid, azelaic acid, sebacic acid, maleic acid, fumaricacid, glutaconic acid, α-hydromuconic acid, β-hydromuconic acid,α-butyl-α-ethyl-glutaric acid, α-β-diethylsuccinic acid, isophthalicacid, terephthalic acid, hemimellitic acid, and1,4-cyclohexane-dicarboxylic acid. Any suitable polyhydric alcoholincluding both aliphatic and aromatic containing aliphatic alcohols maybe used such as ethylene glycol, 1,3-propylene glycol, 1,2-propyleneglycol, 1,4-butylene glycol, 1,3-butylene glycol, 1,2-butylene glycol,1,5-pentane diol, 1,4-pentane diol, 1,3-pentane diol, 1,6-hexane diol,1,7-heptane diol, glycerol, 1,1,1-trimethylolpropane,1,1,1-trimethylolethane, hexane-1,2,6-triol, α-methyl glucoside,pentaerythritol, and sorbitol. Also included with the term "polyhydricalcohol" are compounds derived from hydroxyethyl phenol such as2,2-bis(4-hydroxy-ethyl phenyl)propane, commonly known as ethoxylatedBisphenol A.

The hydroxyl-containing polyester can also be a polyester amide such asis obtained by including some amine or amino alcohol in the reactantsfor the preparation of the polyesters. Thus, polyester amides may beobtained by condensing an amino alcohol such as ethanolamine with thepolycarboxylic acids set forth above or they may be made using the samecomponents that make up the hydroxyl-containing polyester with only aportion of the components being a diamine such as ethylene diamine.

Any suitable polyalkylene glycol (polyether polyol) can be used such asthe polymerization product of an alkylene oxide or of an alkylene oxidewith a polyhydric alcohol having about 2 to about 6 hydroxyl groups. Anysuitable polyhydric alcohol may be used such as those disclosed abovefor use in the preparation of the hydroxyl-containing polyesters. Anysuitable alkylene oxide may be used such as ethylene oxide, propyleneoxide, butylene oxide, amylene oxide, and heteric or block copolymers ofthese oxides. The polyalkylene polyether polyols can be prepared fromother starting materials such as tetrahydrofuran and alkylene oxidetetrahydrofuran copolymers; epihalohydrins such as epichlorohydrin; aswell as aralkylene oxides such as styrene oxide. The polyalkylenepolyether polyols may have either primary or secondary hydroxyl groupsand, preferably, are polyethers prepared from alkylene oxides havingabout two to about six carbon atoms such as polyethylene ether glycols,polypropylene ether glycols, and polybutylene ether glycols. Thepolyalkylene polyether polyols may be prepared by any known process suchas, for example, the process disclosed in the Encyclopedia of ChemicalTechnology, Vol. 7, pp. 257-262, published by Interscience Publishers,Inc. (1951) or in U.S. Pat. No. 1,922,459. Polyethers which arepreferred include the alkylene oxide addition products oftrimethylolpropane, glycerine, pentaerythritol, sucrose, sorbitol,propylene glycol, and 2,2-(4,4'-hydroxyphenyl)propane and blends thereofhaving equivalent weights of from 250 to 5000.

The monovinyl monomer which can be employed in the preparation of thewater-dispersible or water-soluble graft polyester size compositions ofthe invention is present in a major effective amount, generally about 20to about 200 percent by weight based upon the weight of the unsaturatedpolyester used. Preferably about 50 to about 150 percent by weight ofsaid vinyl monomer is utilized. Said vinyl monomer contains only onevinyl group in the monomer and comprises (1) at least one acidicmonovinyl monomer having at least one carboxyl group or (2) mixturesthereof with any monovinyl monomer. Where cross-linked, water-insolublepolyesters are desired, even under basic aqueous conditions,polyunsaturated vinyl monomers are substituted for said acidic monovinylmonomer. Useful monovinyl monomers and polyunsaturated vinyl monomerscontain free radical initiated polymerizable α,β-ethylenic unsaturationand are reactive with and compatible with, preferably solvents for, theunsaturated polyester of the invention. A representative listing ofvinyl monomers from which useful monomers can be selected by one skilledin the art includes styrene, α-methylstyrene, methylstyrene,2,4-dimethyl-styrene, ethylstyrene, isopropylstyrene, butylstyrene,cyclohexylstyrene, benzylstyrene, and the like, substituted styrenessuch as chlorostyrene, 2,5-dichlorostyrene, bromostyrene, fluorostyrene,trifluoro-methylstyrene, iodostyrene, cyanostyrene, nitrostyrene,acetoxystyrene, methyl 4-vinyl-benzoate, and the like; the acrylic andsubstituted acrylic monomers such as acrylonitrile, acrylic acid,methacrylic acid, methylacrylate, 2-hydroxyethyl acrylate,2-hydroxyethyl methacrylate, methyl methacrylate, cyclohexylmethacrylate, isopropyl methacrylate, octyl methacrylate,methacrylonitrile, methyl α-chloroacrylate, ethyl α-ethoxyacrylate,methyl α-acetaminoacrylate, butyl acrylate, ethyl acrylate,2-ethylhexylacrylate, α-chloroacrylonitrile, and the like; the vinylesters, vinyl ethers, etc., such as vinyl acetate, vinyl chloroacetate,vinyl butyrate, vinyl formate, vinyl methoxy acetate, vinyl benzoate,vinyl iodide, vinyl toluene, vinyl naphthalene, vinyl bromide, vinylchloride, vinyl fluoride, vinylidene bromide, vinylidene chloride,1-chloro-1-fluoroethylene, vinylidene fluoride, vinyl methyl ether,vinyl ethyl ether, vinyl propyl esters, vinyl butyl ethers, vinyl2-ethylhexyl ether, vinyl phenyl ether, vinyl 2-methoxyethyl ether,methoxybutadiene, vinyl 2-butoxyethyl ether, vinyl phosphonates such asbis(β-chloroethyl)vinyl phosphonate, vinyl phenyl ketone, vinyl ethylsulfide, vinyl ethyl sulfone, N-methyl-N-vinyl acetamide,N-vinyl-pyrrolidone, vinyl imidazole, divinyl sulfide, divinylsulfoxide, divinyl sulfone, N-vinyl pyrrole, and the like; dimethylfumarate, dimethyl maleate, monomethyl itaconate, t-butylaminoethylmethacrylate, dimethylaminoethyl methacrylate, glycidyl acrylate, andthe like. Any of the other known vinyl monomers reactive under freeradical initiation can be used as would be apparent to one skilled inthe art. The compounds listed above are illustrative and not restrictiveof the monomers suitable for use in this invention.

A representative listing of initiators for free radical initiatedpolymerization from which useful initiators can be selected by oneskilled in the art includes the peroxides, i.e., diacylperoxides, ketoneperoxides, hydroperoxides, sulfonylperoxides, alkylperoxides,percarbonates, i.e., peroxydicarbonates, azo compounds, and others suchas peroxyesters and peroxyketals and specific initiators includinghydrogen peroxide, dibenzoyl peroxide, acetyl peroxide, benzoylhydroperoxide, t-butyl hydroperoxide, di-t-butyl peroxide, lauroylperoxide, butyryl peroxide, diisopropylbenzene hydroperoxide, cumenehydroperoxide, paramethane hydroperoxide, diacetyl peroxide, di-α-cumylperoxide, dipropyl peroxide, diiso-propyl peroxide, isopropyl-t-butylperoxide, butyl-t-butyl peroxide, dilauroyl peroxide, difuroyl peroxide,ditriphenylmethyl peroxide, bis(p-methoxybenzoyl)peroxide,p-monomethoxybenzoyl peroxide, rubrene peroxide, ascaridol, t-butylperoxybenzoate, diethyl peroxyterephthalate, propyl hydroperoxide,isopropyl hydroperoxide, n-butyl hydroperoxide, t-butyl hydroperoxide,cyclohexyl hydroperoxide, trans-Decalin hydroperoxide,α-methyl-α-ethylbenzyl hydroperoxide, Tetralin hydroperoxide,triphenylmethyl hydroperoxide, diphenylmethyl hydroperoxide,α-β-azo-2-methyl butyro-nitrile, α-α'-2-methyl heptonitrile,1,1'-azo-1-cycylohexane carbonitrile, dimethyl-α, α'-azoisobutyrate,4,4'-azo-4-cyanopentanoic acid, azobis(isobutyronitrile), persuccinicacid, diisopropyl peroxy dicarbonate, and the like; a mixture ofcatalysts may also be used. Many other useful catalysts are disclosed inOrganic Peroxides by A. V. Tovolsky and R. B. Mersrobian, IntersciencePublishers, 1954, pages 158-163. These initiators form free radicals bycleavage of the peroxide linkage or other mechanism with heating orradiation or by the action of accelerators or promoters in combinationwith heating or radiation at lower temperatures.

The most common accelerators are cobalt salts and tertiary diamines.Vanadium salts as well as quaternary ammonium salts are also used.Representative examples of accelerators from which useful acceleratorscan be selected by one skilled in the art are N,N-dimethylaniline,N,N-dimethyl-p-toluidine, N,N-dimethyl-p-toluidine, cobalt naphthanate,lauryl mercaptan, cobalt octoate, and vanadium acetylacetonate. Thegraft copolymerization process of the subject invention is generallycarried out at temperatures of about 80° C. to about 200° C., preferablyfrom about 80° C. to about 150° C. Generally from about 0.05% to about5% by weight of initiator based on the weight of the monomer andunsaturated polyester will be employed in the process of the invention.

The free carboxyl group-containing polyester size compositions of theinvention are particularly suited for use in sizing fibers which are tobe woven on a water jet loom. In this textile yarn sizing application,the size which is present on the fibers during the weaving process iswater insoluble but subsequently, the sizing can be rendered easilyremovable by neutralization or partial neutralization of the size duringconventional desizing and scouring treatments wherein an aqueous base isutilized such as sodium and potassium hydroxide, an amine, or sodium andpotassium carbonate, both with or without surfactants. Generallysuitable bases include ammonia, the alkali metal hydroxides andcarbonates and bicarbonates as well as amines such as the tri(loweralkyl) amines (C₁ -C₆) illustrated by triethylamine and trimethylamine.Other useful amines include triethanolamine and morpholine.

The hydroxyl-containing component of the polyester which is a polyhydricalcohol such as an alkylene glycol or a polyester polyol or a polyetherpolyol, is preferably a diol. However, the hydroxyl-containing componentof the unsaturated polyester of the invention can also include a minoramount, preferably up to 20 mole percent of a polyhydric alcohol havinga functionality greater than two such as polyester or polyether polyolcontaining more than two (2) hydroxyl groups per molecule as determinedby the average of the hydroxyl groups per molecule. Suchhydroxyl-containing compounds are well known in the art and arerepresented by compositions listed above. Where it is desirable toinclude a polyol having a functionality greater than two as part of thehydroxyl-containing component of the polyester of the invention, it isgenerally necessary to add a compensating amount of a monofunctionalacid such as stearic or benzoic acid in order to avoid gelatin early inthe polymerization as predicted by the Carothers Equation.

The dicarboxylic acid reactant can also include a minor amount of apolycarboxylic acid reactant having a functionality greater than two.Thus, preferably up to 20 mole percent of such a polycarboxylic reactantcan be used to replace a portion of the dicarboxylic acid reactants.Representative polycarboxylic acid reactants having a functionalitygreater than two are well known in the art. They include such acids astrimellitic acid, hemimellitic acid, trimesic acid, 1,2,3,4-benzenetetracarboxylic acid and the corresponding anhydrides thereof where theyexist. Where it is desired to include a polycarboxylic acid componenthaving a functionality greater than two as part of the dicarboxylic acidreactant component of the polyester of the invention, it is necessary toadd a compensating amount of a monofunctional alcohol such as ethanol orpropanol in order to avoid low molecular weight products and gelationearly in the polymerization as predicted by the Carothers Equation. Suchpolyfunctional reactants can also be added at the end of thecondensation reaction to produce the unsaturated polyester of theinvention without serious gelatin effects. In this case, a compensatingmonofunctional alcohol would not be required.

The novel graft polyester compositions of the invention containing freecarboxyl groups are particularly useful in the sizing of syntheticorganic fibers and blends thereof with natural fibers, particularly thesizing of textile yarn prior to weaving. In addition, the sizing ofglass fibers and filaments is accomplished using said graft polyesters.For instance, the synthetic organic fibers such as the hydrophobicfibers illustrated by polyacrylics, polyamides and polyester fibers, forinstance, those prepared from linear polyesters such aspoly(ethyleneterephthalate) are effectively sized either alone or inblends with other natural and synthetic organic fibers.

The graft polyester size compositions of the invention are particularlysuited for the sizing of textile yarn since they exhibit excellentadhesion to synthetic fibers as exemplified by those fibers listedabove. It is thereof intended to replace the use of such prior artsizing compounds as polyvinyl alcohol and carboxymethyl cellulose aswell as other prior art water-soluble linear saturated polyester sizecompositions, for instance, those containing sulfonate groups in thepolyester chain. As is well known, synthetic, organic, hydrophobicfibers such as polyesters are characterized by their lack of reactivesites in the molecular structure which would permit extensive hydrogenbonding to take place and thus facilitate adhesion of a size to thefiber, as is the case with nylon and rayon fibers. Thus, because of itsexcellent adhesion properties, the graft polyester size of the inventionis particularly suited for use in sizing polyester fibers alone or inblends with spun or continuous filament fibers of cellulose acetate,polyacrylics, viscose rayon, as well as natural fibers such as cottonand wool.

The unsaturated polyester-vinyl monomer size compositions of theinvention when used as glass fiber sizing compositions also can begrafted in situ and applied to the glass fibers during their formation.Such sizing particularly suits such fibers for incorporation intomolding compounds as reinforcing materials. As disclosed in U.S. Pat.No. 3,936,285, water-based sizing compositions are applied to the glassfilaments as they are formed by drawing and the strand of glass fibers,which consists of gathered fibers, is then wound on a forming package.Subsequently, the forming package is dried in an oven and it is duringthis drying stage that the solids of the water-based sizing compositionhave a tendency to migrate from the inside of the package to the outsideof the package as the water contained in the sizing composition isvolatilized. The sizing compositions of the invention are useful in thesizing of glass fibers during formation of the fibers as there is littleor no tendency of the sizing to migrate subsequent to application to theglass strands since the sizing compositions of the invention are appliedwithout the use of solvent and hardening of the composition by graftpolymerization can take place subsequently either by at least one of theapplication of heat or exposure to irradiation. Because of the chemicalsimilarity of the sizing compositions of the invention to resin matricesutilized in combination with glass fibers where glass fibers areutilized to reinforce a molded article, that is, an unsaturatedpolyester resin as the resin matrix, the sized fiber demonstratesexcellent adhesion to the resin matrix which can result in improvedphysical properties in the molded article.

The unsaturated polyester-vinyl monomer size compositions of theinvention, in addition to being hardened, or grafted, by the applicationof heat, can be hardened by the application of both heat and radiationor radiation alone, particularly ultraviolet radiation where thecomposition includes an appropriate free radical generating initiator.The graft polyesters of the invention are also suited for adhesive andcoating applications including flexible printing ink compositions sincethe carrier solvents as a part of the coating composition areeliminated. Therefore, in using the graft polyesters of the invention,in such applications as printing inks for lithography, organic solventvapors are not evaporated into the atmosphere or alternatively,extensive solvent recovery equipment is not employed to prevent such airpollution. In addition to the radiation hardening of the graftpolyester-vinyl monomer compositions of the invention utilizingultraviolet radiation, said compositions of the invention are curableupon exposure to ionizing radiation, that is, that radiation created bythe emission of electrons or highly accelerated nuclear particles suchas neutrons, alpha particles, etc.

In order to evaluate the adhesive strength of the graft polyester sizeof the invention, two pieces of 20 mil poly(ethylene terephthalate)sheeting measuring one inch by three inches are overlapped to form a oneinch square after applying a drop of the graft polyester of theinvention which is then placed on another piece of polyester film. Theassembly is heated for a period of about one minute at a temperature of110° C. under a one pound weight so as to bond the two films together. Astrongly-adhering coating was obtained.

The tackiness of films of the graft polyester of the invention wasevaluated in order to determine the suitability of the compositions as atextile size. Films five mil thick were cast onto 20 milpoly(ethyleneterephthalate) sheeting from blends of an unsaturatedpolyester and an acidic vinyl monomer as indicated in the examples andthe film was evaluated subsequent to graft polymerization in situ andafter conditioning for 24 hours at 65 percent relative humidity.Subjective evaluation of tackiness indicated that the films producedwere completely free of tackiness.

Since the thorough removal of the size composition from the yarnsubsequent to weaving is often of critical importance, it is necessarythat a useful size composition exhibit excellent solubility in theordinarily used dilute caustic desizing solution. The graft polyestersize compositions were thus evaluated for solubility in dilute causticsolutions by preparing five mil films of the graft polymerized polyestercompositions of the invention which were conditioned for 24 hours underconditions of 70° F. and 65 percent relative humidity. It was found thatfilms made from the graft polyester size compositions of the inventionare dispersed or dissolved in dilute caustic solutions but are stable inneutral or acid solutions.

The in situ polymerized graft polyester sizes of the invention can beapplied to the yarn as sizes therefor by any convenient means wherebythe yarn is contacted with a combination of the unsaturated polyester ofthe invention and a vinyl monomer. Since the size compositions of theinvention are solventless, the required proportion of size can beapplied to the textile fiber without the need to evaporate carriersolvents. For instance, the textile yarn can be passed through saidunsaturated polyester-vinyl monomer mixture containing a free radicalgenerating initiator, at any convenient linear rate of speed, themixture being maintained at any convenient temperature so as to providesufficient fluidity so as to obtain the desired coating weight on thefibers. Generally, application temperatures of about 20° C. to about150° C., preferably ambient temperature up to about 125° C. are used.The rate of speed at which the fibers are coated by passing them throughthe mixture comprising the unsaturated polyester-vinyl monomer will beinfluenced by the means utilized to graft polymerize the vinyl monomerwith the polyester subsequent to application to the yarn. For instance,where infrared or conduction or convection heating is utilized, i.e.,the coated fibers are passed over oil- or steam-heated drums, it isgenerally desired to maintain said polyester-vinyl monomer mixture at atemperature of about 80° C. to about 200° C. for about 0.1 minute toabout two minutes in order to effect grafting. The time required being afunction of the half life of the initiator system used. Alternatively,where radiation, i.e., ultraviolet radiation is used to effect thegrafting of the vinyl monomer onto the unsaturated polyestercompositions of the invention, greater flexibility in speed of thesizing operation is obtained where an initiator system is selectedhaving a suitable half life upon exposure to ultraviolet radiation.

Generally, a size coating weight or add-on of about three to about tenpercent, preferably about four to about eight percent by weight basedupon the weight of the fibers is utilized in sizing synthetic organicfibers such as poly(ethyleneterephthalate). Generally, inert additivesused in the prior art fiber sizing compositions such as lubricants,plasticizers, softeners, dyes, defoamers, overwaxes, penetrants,hygroscopic agents and stabilizers can be incorporated, whereapplicable, into the polyester-vinyl monomer sizing compositions of theinvention or applied to the fibers as pre- or after-treatments. Suchadditives which do not interfere with the graft polymerization and areeasily removed in the desizing stage are useful.

When it is desired that the graft polyester size remain permanently inthe fabric and remain insoluble in water even in the presence of a base,the unsaturated polyester containing a minor effective proportion of atleast one of an α,β-ethylenically unsaturated dicarboxylic acid orpolyhydric alcohol reactant can be cross-linked and water-insolubilizedeven in the presence of a base by contacting it during grafting with avinyl monomer comprising a polyunsaturated vinyl monomer such as divinylbenzene or ethylene dimethacrylate. Water-insolubilization under basicconditions can also be effected during or after grafting bycross-linking said graft polyester using a cross-linking resin such asan aminoplast, i.e., a phenolformaldehyde, ureaformaldehyde,melamineformaldehyde or methylated ureaformaldehyde resin. For instance,the graft polyester size can be cross-linked subsequent to itsdeposition on the fibers by passing the sized fiber or fabric through asolution of the cross-linking agent containing a catalyst therefore andsubsequently drying and heating to cure, or cross-link, the graftpolyester. Such a process is particularly suited to the production offabrics having permanent creases therein since the final stage in thecross-linking process, that is, the heating and curing stage, can bedelayed subsequent to the application of the aminoplast or othercross-linking resin with catalyst to the sized fiber or to the sizedfabric. Suitable cross-linking resins are listed above. These are wellknown in the textile finishing art and their synthesis and selection iswithin the skill of those persons skilled in the art. Generally, thecross-linking resin is applied by immersing the textile fabric in asolution or dispersion thereof containing 2 to 90 percent by weight ofthe cross-linking resin, removing the fabric, squeezing excess solutionfrom the fabric, and heating the fabric at cross-linking temperatures offrom about 200° to 450° F. and preferably from about 225° F. to about300° F.

Because the graft polyesters of the invention prepared using monovinylacidic monomers can be converted from the water-insoluble free-acid formto the water-soluble salt form by reacting said graft polyesters with abase, such compositions find use, in addition to their uses in thetextile field, as adhesives in the paper industry to take the place ofthe so-called repulpable hot-melt adhesives. Use of said graftpolyesters as adhesives is particularly advantageous since they can beapplied, for instance, as bookbinding adhesives, as solventless mixtureswhich can be readily hardened, or grafted, by the application of heat orby irradiation as discussed above. The graft polyesters of the inventionare particularly advantageous over the prior art hot-melt polyesteradhesives which are repulpable in that, generally, little or no heatingis necessary to provide fluid mixtures of the unsaturated polyester ofthe invention and the vinyl monomer. The fluid mixtures can be readilyapplied to substrates prior to the grafting operation and converted to asolid resinous material which is water-insoluble until reacted with abase during the repulping operation.

The graft polyesters of the invention are prepared using an unsaturatedpolyester having an acid number which is generally of about 2 to about40, preferably about 4 to about 20, and most preferably about 7 to about15. Thus, prior to grafting, the polyester has an acid number such thatan effective amount of an acidic monovinyl monomer can be grafted ontothe unsaturated polyester to provide carboxylic acid sites sufficient toprovide an acid number of about 50 to about 750, preferably about 100 toabout 500, and most preferably about 150 to about 300. Uponneutralization or partial neutralization with a base, awater-dispersible or water-soluble size results which is easily removedin the usual textile caustic scour desizing operation. Throughout thisspecification and claims, when acid number is referred to, it isunderstood to refer to the number of milligrams of potassium hydroxidenecessary to neutralize the non-volatile content of one gram of theunsaturated polyester or the graft polyester of the invention. Themolecular weight of the unsaturated polyester of the invention isgenerally about 3000 to about 15,000, preferably about 4000 to about10,000 and corresponds to a carboxylic acid number in the unsaturatedpolyester of about 4 to about 20, preferably about 7 to about 15.

The following examples will further illustrate the nature and method ofthe preparation of the graft polyester compositions of the invention andtheir use as sizing compositions for textile fibers. The examples areintended to illustrate the various aspects of the invention but are notintended to limit it. When not otherwise specified throughout thespecification and claims, temperatures are given in degrees centigradeand parts, percentages and proportions are by weight.

EXAMPLE 1

An unsaturated polyester of the invention was prepared by charging 558grams of isophthalic acid, 13.7 grams of maleic anhydride, and 409 gramsof diethylene glycol to a two liter resin flask equipped with stirrer,thermometer, and vacuum take-off. The mixture of ingredients was spargedwith nitrogen and slowly heated in an oil bath to a temperature of 167°C. After adding four grams of tetrabutyltitanate catalyst, thetemperature was slowly increased and condensate first appeared at 185°C. After ten hours, the temperature was slowly raised to 210° C. and 74percent of the theoretical distillate was collected. The nitrogen spargewas stopped at this point and the reaction mixture was placed under avacuum of less than 0.1 millimeters of mercury. After six hours undervacuum, the acid number was progressively decreased to 4.1. The viscoussyrupy product obtained was decanted onto a Teflon sheet where it cooledto a hard tough resin. Further cooling with dry ice allowed it to becrushed readily into small chunks.

EXAMPLE 2

Utilizing the unsaturated polyester prepared in Example 1, an equalweight of said polyester was mixed with an equal weight of acrylic acid.To this liquid composition was added 2.5 percent by weight based uponthe weight of the total mixture of 2,2'-azobisisobutyronitrile asinitiator. The homogeneous mixture was liquid at room temperature and offluid viscosity (Gardner U). In order to test its adhesion to polyester,the mixture was coated onto poly(ethyleneterephthalate) sheeting andplaced in an oven preheated to about 120° C. After one minute, thecoated sheets were removed and cooled. The liquid coating had formed atough, elastic, strongly-adhering coating exhibiting no tackiness.

EXAMPLE 3

Utilizing the sizing mixture of Example 2, poly(ethyleneterephthalate)yarn was sized with said mixture by applying the mixture to the yarnutilizing an Atlas replenished drop applicator. The yarn wassubsequently heated using infrared radiation, passed around a heateddrum maintained at a temperature of 110° C. to about 120° C., andsubsequently wound on a take up bobbin. It was found that the sizedyarn, after heating approximately 0.5 to about 1 minute subsequent toapplication to the yarn, was converted to a non-tacky coating suitableas a size.

EXAMPLE 4

Using the size mixture of Example 2, films of about 5 mil thickness werecast on poly(ethyleneterephthalate) sheeting and oven heated as inExample 2 to effect grafting. The assembly was then soaked in water atambient temperature for 48 hours without apparent change in filmcharacteristics. When these films were placed instead in a diluteaqueous caustic solution, the film was readily dissolved off thesheeting.

EXAMPLE 5

Using the unsaturated polyester of Example 1, an equal weight of saidpolyester is mixed with methacrylic acid. To this composition there isadded 2.5 percent of 2,2'-azobisisobutyronitrile as initiator and themixture is coated onto poly(ethyleneterephthalate) yarn according to theprocedure of Example 3.

EXAMPLES 6-7

Using the procedure and the sizing mixture of Example 3, the size isremoved from the fiber by exposing separately the sized fiber todesizing solutions as follows:

aqueous sodium hydroxide--0.1 mol solution

aqueous ammonia--0.5 mol solution

EXAMPLES 8-11

Example 2 is repeated substituting the following initiators for the azotype initiator used in Example 2; benzoyl peroxide, lauroyl peroxide,methyl ethyl ketone peroxide and tertiary butylperoxybenzoate.

EXAMPLE 12

Example 1 is repeated substituting an equal parts by weight mixture ofdiethylene glycol and ethylene glycol for the diethylene glycol ofExample 1.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:
 1. A cross-linked graftpolyester comprising the reaction product ofa mixture of apolyunsaturated vinyl monomer with an acidic monovinyl monomer having atleast one carboxyl group with and unsaturated polyester which thereaction product of:(1) at least one dicarboxylic acid reactant selectedfrom the group consisting of dicarboxylic acids, correspondingdicarboxylic anhydrides, dicarboxylic acid esters, and theircorresponding acyl halides and (2) at least one polyhydric alcoholcomprising (a) a diol or (b) a mixture of a diol and up to 20 molepercent of a polyhydric alcohol having a functionality greater than 2based upon 100 mole percent of said polyhydric alcoholwherein a minoreffective proportion of said dicarboxylic acid reactant or saidpolyhydric alcohol reactant is α,β-ethylenically unsaturated.
 2. Thecomposition of claim 1 wherein said dicarboxylic acid reactant is amixture of a saturated aromatic dicarboxylic acid treatment and about 1to about 10 mole percent of an α,β-ethylenically unsaturated aliphaticdicarboxylic acid reactant and said polyhydric alcohol is a diolcontaining two to eight carbon atoms and said monovinyl monomer isselected from at least one of the group consisting of acrylic acid andmethacrylic acid.
 3. The composition of claim 2 wherein said saturatedaromatic dicarboxylic acid reactant is isophthalic acid, saidunsaturated aliphatic dicarboxylic acid reactant is maleic acid oranhydride, said monovinyl monomer is acrylic acid, and said diol is amixture of ethylene glycol and diethylene glycol.
 4. The composition ofclaim 2 wherein said polyunsaturated vinyl monomer is a divinylcompound.
 5. The composition of claim 4 wherein said divinyl compound isselected from the group consisting of at least one of divinyl benzene,ethylene dimethylacrylate, divinyl sulphide, divinyl sulfoxide, anddivinyl sulfone.
 6. The composition of claim 5 wherein said divinylcompound is selected from the group consisting of at least one ofdivinyl benzene and ethylene dimethacrylate.